Sheet impact cushion device



G. F. LYTLE SHEET IMPACT CUSHION DEVICE Dec. 1 9, 1967 2 Sheets-Sheet 1 Filed Sept. 23, 1965 INVENTOR. GEORGE F. LYTLE BY W M,,J

ATTORNEYS Dec. 19, 1967 G. F. LYTLE SHEET IMPACT CUSHION DEVICE 2 Sheets Sheet 2 Filed Sept. 23, 1965 INVENTOR. GEORGE F. LYTLE ATTORNEYS United States Patent 3,358,993 SHEET IMPACT CUSHION DEVICE George F. Lytle, St. Louis, MO., assignor to Alvey Conveyor Manufacturing Company, St. Louis, Mo., a corporation of Missouri Filed Sept. 23, 1965, Ser. No. 489,508 6 Claims. (Cl. 271-86) ABSTRACT OF THE DISCLOSURE A cushion device to absorb impacts from sheet material projected into a stacking area, fluid pressure means to fix the cushion device in predetermined position and to provide secondary shock cushioning means for the device, and a particular arrangement of canted impact absorbing ribs replaceably mounted on the cushion device.

This invention relates to improvements in sheet impact cushion devices for applications in high speed sheet handling and stacking apparatus.

In apparatus for receiving sheet material from a continuous feed line and placing such material in stacks on pallets or the like it is a problem of manipulating the fast moving sheets in rapid succession onto a neat stack. It is especially a problem of absorbing the energy of the sheets in a short distance Without incurring rebound movement so that the sheets can be substantially precisely stacked. In connection with the foregoing problems it is also a problem to maintain cushion devices in an effective condition for long periods of time due to the damage of high speed impact and the cutting action of the edges of the sheets as they strike the cushion. Furthermore, it is important that in stopping the sheets there be no material damage done to the sheets.

In the present invention it is an object to provide an improved cushion device that will stop moving material such as metal, glass, fiber, plastic or wood sheets.

It is an object hereof to rapidly bring the sheet material to a stop after leaving the feeding conveyor apparatus and to quickly and accurately stack the same.

Another object of the invention is to provide an improved cushion device that will carry out the foregoing objects and protect the sheet material from damage while absorbing the impact.

A further object of the invention is to provide an impact cushion with a series of shock absorbing elements made of resilient material that may be varied to suit the type of material of which the sheets are made and the speed of movement thereof so that the most effective conditions of impact absorption can be selected.

It is also an object of the invention to provide a multibladed cushion device that will control the stopping position of sheet material and be resistant to cuts.

Yet another object of the invention is to provide a bladed impact cushion device that will allow blade replacement and in which the blades are formed to build up resistance progressively and distribute the impact shock with a minimum of rebound effect, such that there is an automatic feature of reaction to accommodate both light gauge and heavy gauge sheet material.

In a preferred example of the cushion device there is provided a series of individual impact absorbing blades of tapered form, with the blades set in groups directed at opposite angles, the effect of which is to absorb impact in bending of the blades and to control the lateral drift of the sheets and maintain directional stability. The blades are formed of resilient material having a range of resiliency (durometer) that will allow a wide range of damping and impact shock absorbing capacities.

In view of the foregoing it is another object of the invention to provide molded individual impact blades to allow for rapid replacement in the event of damage thereto, as well as to allow for desired position adjustments of the blades.

It is yet another object of the invention to provide an improved cushion device of the foregoing character that acts as the primary impact cushion and to combine therewith secondary impact cushion means for bringing the sheet material to a desired stopping location relative to the stack to be formed.

The foregoing objects and advantages will be more fully pointed out in connection with the following disclosure of the preferred form of the invention, when considered in connection with the accompanying drawings, wherein:

FIG. 1 is a side elevational view of a sheet stacking apparatus in which the present invention is incorporated, portions of the apparatus being broken away;

FIG. 2 is an enlarged and fragmentary view in side elevation of the improved cushion device seen in FIG. 1;

FIG. 3 is a perspective view of one cushion device in a preferred form;

FIG. 4 is a perspective view of another cushion device similar to that in FIG. 3;

FIG. 5 is an end view of a cushion blade;

FIG. 6 is also an end view of a modified cushion blade; and

FIG. 7 is a schematic view of a control system applicable to the apparatus of FIG. 1.

In FIG. 1 the apparatus 10 is a sheet stacking apparatus having a main frame 11 with a sheet feeding conveyor assembly 12 at one side and a sheet stacking frame 13 supported in cantilevered position from the main frame 11 by suitable tension rods 14. The stacking frame 13 is positioned above the floor 15 of the working area and over a pallet 16 on which the sheet material S is stacked.

As may be seen in FIGS. 1 and 2 the stacking frame has spaced side members 17 and 18 (the latter member 18 being broken away so that the means between may be identified) connected by opposite cross members 19 and 20. The frame supports in suitable manner a longitudinal track 21 that is parallel to side members 17 and 18, and spaced above the track is a longitudinal mandrel 22 that is parallel with the track 21. A frame 23 is slidably mounted on track 21 and is provided with brackets 24 and 25 for rollers 26 riding on the upper surface of the track 21. The brackets 24 and 25 also carry guide rollers 27 that follow the mandrel 22 and aid in keeping the track 21 and mandrel 22 in spaced position. The frame 23 is movable along the track by means of a drive chain 28, one end 28A of the chain being connected to bracket 24 and the opposite end 283 is connected to the other bracket 25. The drive chain is trained over a sprocket 29 at one end of the track, extends through the track and out over an opposite sprocket 30. The motion of the frame 23 is controlled by a hand Wheel 31 located adjacent the outer end of the stacking frame 13 near cross member 20.

Connected to the frame 23 by suitable bracket means 32 is a brake device 33 having suitable air operated friction means (not shown) therein supplied with pressure fluid by a conduit or hose 34. The wheel 31 is turned to position the frame 23 as desired and the brake device 33 is then energized to lock the frame 23 against displacement along the track 21.

The stacking frame 13 carries sheet side guides 35 and 36 suspended from the side members 17 and 18 respectively. The guides control the longitudinal movement of the sheets S from the time each leaves the conveyor 12 until each reaches the stack thereof On the pallet 16.

As seen in FIGS. 1 and 2, the frame 23 is provided with a pair of pivot brackets 37 (one being shown) and with ,a depending arm 38 spaced from the pivot bracket 37 as best seen in FIG. 2. A frame member 39 having a planar face plate 40 is suspended from the brackets 37 on lugs 41 (see FIG. 3) by a pivot pin 42. A pressure fluid cylinder 43 forming the secondary cushion means has one end provided with a clevis 44 connected by a pivot pin 45 to the outer end of arm 38. The rod 36 slidably movable in the cylinder 43 on a piston (not shown) has its outer end provided with a clevis 47 that is pin connected to the rear side of the face plate 40, as may be seen in FIG. 2.

As may be seen in FIG. 3, the face plate 40 carries a plurality of primary cushion elements 48 set in vertical positions and arranged in two groups A and B. Group A elements 48 are canted or angled rearwardly and group B elements 48 are canted or angled forwardly (as viewed in FIG. 3). The face plate carries detachable cleats 49 at each end and intermediate cleats 50 between the individual blades 48. The cleats serve to removabl secure the base of the blades 48 to the face plate 40, as will be more particularly described in FIGS. 4 and 5. The oppositely canted or angled groups A and B of blade elements 48 serve to control lateral or sidewise drift of the sheets S as each strikes the blades, and the blades as a total group react to impact in bending to serve as the primary cushioning means. As the impact is absorbed by the blades in bending the force is gradually transferred by backward pivoting of the face plate 40 to the secondary cushioning means 43. The secondary means 43 therefore builds up energy in the pressure fluid supplied by hose 51 and this energy is used to return the face plate to its starting position of FIG. 1 in a gradual reaction and using the piston as the stop limit. This action checks rebound and accurately locates the sheet S so that it drops upon the pallet 16 in a neat and aligned stack (FIG. 1).

Attention will now be directed to FIGS. 4 and for further details of the primary cushion device, it being understood that the same will apply to the disclosure of FIG. 3. In FIG. 5 a typical blade 48 is shown as having a base 52 formed with lateral wings 53 providing a notch 54 on the upper side. The body of the blade 48 extends angularly outwardly from the base 52 at approximately a mean angle of 21 from the vertical axis line X. The sides 55 and 56 of the blade 48 are tapered relative to the vertical axis line X, side 55 being approximately 19 and side 56 being approximately 23". Thus, the blade 48 has a tapered configuration toward its outer flat end 57.

As can be seen in FIG. 4 a group A of blade elements 48 are located on the face plate 40 canted to the left. The end cleat 49 is formed with side locks 49A that match the notches 54 in the side wings 53 of the blades. Suitable screws 58 secure the cleats 49 in position. The intermediate cleats 50 are similarly formed with side locks 50A to engage in the notches 54 of two adjacent blades 48. It is evident that the assembly of blades 48 on the face plate 40 is made by progressively mounting the blades and cleats and tightening down on the screws 58. The blades 48 are all identical so that group B is made up by reversing the blade positions relative to group A.

In FIG. 6, the modified blade 60 has a base 61 with wings 62, each having a notch 63. The blade portion is canted at an angle of about 21 from the vertical axis Y. Side 64 is formed at an angle of about 23 to the axis Y, and the opposite side 65 has an angle of about 19 to axis Y. The outer end 66 of the blade is rounded. The blade 60 of FIG. 6 may be assembled on the base plate 40 as heretofore described, and cleats 49 and 50 are again used to secure the blades in positions where the groups thereof are oppositely outwardly canted.

In FIG. 7 there is shown schematically a pressure fiuid system in which the hose 34 has several slack loops L extending to a control valve 67 and thence to a pressure regulator as. A source of pressure fluid is supplied by conduit 69 through the filter 70 to a branch 71 that connects to the regulator 68. The opposite branch conduit 72 leads to a pressure regulator 73 and the other side of this regulator is connected to hose 51 having several slack loops L.

When adjusting the system of FIG. 7 to set the secondary cushion device 43, the valve 67 is turned to shut oil the supply to hose 34 and open the vent port 67A so that there is no braking action at the means 33. Regulator 73 is then set for the desired pressure to decelerate the sheets S through the means 43. The valve 67 is then opened to set the brake device 33 and the regulator 68 is set for the desired pressure that will prevent creep of the brake device 33 when subjected to the impact forces generated by the sheets S. As a sheet strikes the primary cushion blades 48 (or 60) the initial force is absorbed and the frame 39 pivots backwardly to force the rod 46 into the cylinder 43. The piston in the cylinder compresses the fluid in hose 51 thus increasing the pressure and storing up energy which returns the rod 46 to its normal starting position and sets the primary cushion blades 48 in position for the succeeding sheets S.

In the foregoing description two distinct cushioning means 48 and 43 have been combined to provide a positive and highly effective impact absorbing system. The blades 48 react in bending to take the initial high impact forces and the frame 39 transmits the remaining shock to the secondary means 43. The primary means is the group of blades 48 formed of resilient material (such as polyurethane or similar material) having a selected durometer usually within the range of 60 to 90. Each blade 48 is a molded elongated member having a tapered shape to increase its bending stiffness and a broad base 52 to give it an automatic feature of reacting in lesser degree to very light gauge sheets than to heavy gauge sheets that have higher impact loads. In this Way the blades have a self correcting action to variances in sheet gauge or impact forces.

The canted angle for the blades is to control the force components of the impact load and have high axial components (lengthwise of the blade) and relatively low components in the bending direction.

The selection of the durometer for the blade material allows wide ranges in damping and shock absorbing capacities for the over-all cushion device. The blades are molded strips and are all identical in shape so that they may be interchanged or replaced in the event one or more blades are damaged or become excessively worn. In providing separate cleats the individual blades can be moved vertically on the face plate to present an unworn point of impact and thus allow considerably more useful life per blade and in the overall use of the cushion device.

The secondary cushion device 43 is a pressure fluid system and may conventionently utilize air from any suitable factory source. The means 43 absorbs the remaining impact load not absorbed by the blades 48 or 60. In its action the frame 39 is allowed to pivot about pin 42 (FIG. 2) to the outer limit of piston 46A striking the end of the cylinder having the vent port 43A. Opposite movement occurs as the device 43 yields in its lengthwise direction. In yielding the device 43 builds up pressure at the back of piston 46A which is related with the hose system 51 back to the regulator 73 where it may be controlled to provide any pressure which will give the optimum cushioning effect for the load conditions. In this system, as soon as the impact load is neutralized the stored energy of the pressure fluid in line 51 will force means 43 to return to its normal position where the dual cushion system is ready for the next sheet.

It is, of course, understood that the blade 60 in FIG. 6 may be used in place of the blade 48. Also the angle of the blade axis to the perpendicular X or Y is such that the impact load parallel to the X or Y direction develops a component along the blade length that is very high relative to the component normal to the blade length. For a light gauge sheet the major portion of the impact force a is absorbed without a great deal of blade bending and the secondary means 43 quickly performs its functions of dissipating the final impact shock and relocating the plate 40 with its blades 48 (or 60) thereon. As the sheet gauge increases the blades react more in bending for the initial impact and the forces are then transmitted through the base of the blades to the face plate 40 and into the cushion means 43. The tapered shape of each blade controls the impact force absorption first in bending at and near the ends 57 (or 66) of the blades, and then by a firm build-up in the resistance along the length of the blades. The unit forces are initially high, but as more of the impact force reaches the broad base 52 (or 61) the unit forces are decreased, thereby improving the cut resistance of the blades. In the event of damage, the individual blades may be replaced or relocated and there is no need to replace an entire cushion.

The foregoing disclosure will enable those skilled in this art to make and use this invention and it is understood that equivalent means, parts and apparatus is included in the scope of the appended claims wherever possible.

What is claimed is:

1. In an impact cushion system for sheet stacking apparatus having sheet feeding means to deliver successive sheets to a stacking station, the improvement of primary cushion means carried by the apparatus at a limiting margin of the sheet stacking station, pressure fluid responsive brake means to fix said primary cushion means in position, pressure fluid responsive secondary cushion means connected to said primary cushion means, a source of pressure fluid connected to both said brake means and secondary cushion means, and separate pressure controlling means in said pressure fluid connections to said brake means and secondary cushion means.

2. A cushion device for sheet stacking apparatus comprising a frame having a flat face surface, a plurality of strip blade-s seated on said face surface and extending therefrom in cantilevered relation, and cleat means connected to said face surface and alternating between said strip blades, said cleat means engaging adjacent stri blades and securing the blades in position.

3. The cushion device set forth in claim 2 wherein each strip blade has a flat base end and notches extending along each side of said base end, and said cleat means is provided with marginal lips engageable in said notches to positively secure said strip blades to said face surface with said flat base ends seated thereon.

4. The cushion device set forth in claim 3 wherein each strip blade has a tapering body with a free outer end, said body being canted relative to said face surface at an angle of about 2.1 degrees.

5. The cushion device set forth in claim 3 wherein each strip blade has its opposite surfaces convergently directed toward an outer free end, the included angle between said convergent surfaces being approximately four degrees, and said strip blade being canted-relative to the flat base end thereof.

6. The cushion device set forth in claim 5 wherein said strip blade is formed of moldable material of resilient material having a hardness characteristic of between and durometers.

References Cited UNITED STATES PATENTS 2,821,391 1/1958 Buccicone 271-86 M. HENSON WOOD, JR., Primary Examiner. R. A. SCHACHER, Assistant Examiner. 

1. IN AN IMPACT CUSHION SYSTEM FOR SHEET STACKING APPARATUS HAVING SHEET FEEDING MEANS TO DELIVER SUCCESSIVE SHEETS TO A STACKING STATION, THE IMPROVEMENT OF PRIMARY CUSHION MEANS CARRIED BY THE APPARATUS AT A LIMITING MARGIN OF THE SHEET STACKING STATION, PRESSURE FLUID RESPONSIVE BRAKE MEANS TO FIX SAID PRIMARY CUSHION MEANS IN POSITION, PRESSURE FLUID RESPONSIVE SECONDARY CUSHION MEANS 